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Saturday, August 2, 2014

School lunches: Measure twice - cut once

“History doesn’t repeat itself, but it does rhyme” Mark Twain

Maureen Ogle, in her book “In meat we trust”, reminds us that
school lunches have always been on the menu of food controversies. In 1926, the
New York School Board banned frankfurters from school lunches. She writes that:
“The board’s lunch director explained that the food was unsuited to students’
nutritional needs” The director went on to say that: “The sausage was so heavy
that when children ate it, they neglected to eat green stuff and milk”. And
you’ve guessed it – no data were gathered upon which to construct evidence
based policy. The director simply looked into his or her heart in search of
wisdom. The issue of school lunches lingers on and whilst I want to end on a
positive note, I will cite three studies which all show that poorly informed or
misinformed interventions in food choice to improve nutritional balance in
school lunches can back fire.

Case 1. A group
from Tufts University examined the effect of three years of intervention in the
US National School Lunch Programme to reduce total fat and saturated fat intake[1].
They observed that as the % of calories in lunches decreased, the % of calories
from fat increased. This is known as the sugar-fat seesaw. Basically, if one
reduces the level of fat in a child’s energy supply, children will compensate
for the loss of fat by eating higher amounts of other foods and time after
time, it has been shown that as you lower fat, you raise sugar. So, in today’s
terms where sugar is popularly perceived to be utterly toxic, would one
describe the reduction in total fat and saturated fat intakes as a success or
would the increase in % energy from sugars be seen as a failure. This writer
would deem it a success as fats and especially saturates are directly
implicated in elevated plasma cholesterol on the basis of dozens of randomised
controlled feeing studies while almost none exist for sugar at the normal or
even slightly normal levels of intake.

Case 2. Fruit and
vegetable intake are common targets in school lunch programmes and the general
belief is that because they have a low energy density (fewer calories per unit
weight) that higher intakes will reduce energy intake. Researchers from the
University of Wiscanson-Maddison studied food choice in school canteens using
digital imaging to identify foods selected and portion size[2].
They studied schools taking part in the Farm to School project. They found that
whereas fruit and vegetable intake increased, the intake of other foods
decreased such that energy intake remained constant. Thus if the objective was
to reduce energy intake, the project failed. But a higher intake of low-salt,
low fat fruit and vegetables would reduce overall the negative targets of foods
(fats, saturates etc.) and thus the project should be deemed a success.

Case 3: Brian
Wansink and his colleagues at Cornell University, reported on a pilot study
evaluating the consequences of banning chocolate milk in school cafeterias[3].
Chocolate flavoured milk represents about two thirds of all mile in the US
school cafeteria system. In 11 Oregon schools, chocolate flavoured milk was
banned from the lunch menu and the group from Cornell used data gathered in the
National School Lunch Program to assess the success or otherwise. Total milk
sales fell by 10%. White milk increased but some 29% of this non-flavoured milk
was wasted, that is unfinished by the students. In all, the numbers of children
using the School Lunch Program fell by 7%. Success or failure? Once again I
would say the outcome could have been predicted if someone had invested funds
in attitudinal research, which would have saved a lot of money and effort.My father, a carpenter, always used the phrase: “Measure twice – cut once”. In effect, these school lunch managers, in all three cases never measured even once. But they were all mad keen to cut!

Which brings us to a major recent study from the University
of Chicago, which carried out a survey of 557 representative schools to assess
the impact of the updated standards of the National School Lunch Program[4].
The ratio of “agree”/ “agree strongly” to “disagree”/ “disagree strongly” that
“students generally seem to like the new school lunch” was about 70:30. This
contrasts with the opinion: “At first, students complained about the new lunch”
where 57% agreed or agreed strongly. So, slowly the students absorbed the newer
healthier lunches. About 2/3 students have fewer complaints about the new
lunches and the same number doesn’t seem concerned about the changes. One main
area of complaint was the withdrawal of pizzas from some school menus. Students
were happy with healthier pizzas but not happy with the absence of any pizza
option. So this is a positive note for innovation school lunches. However, the
more that innovation is built on a priori
data, the more likely it is to be successful and, regrettably, the general
trend is to cut and not measure in advance.

Here in the EU, where national policies on school lunches
differ according to member state, the Commission has published a very useful
overview of existing practices and has set the scene for future joint action to
help improve the nutritional quality of school lunches[5].

One area of public health nutrition that is badly missing is
the measure of the impact of school lunches on the student’s overall daily
dietary performance. In other words, for how many children does the school
lunch counter balance poor dietary practices at home and outside the home and
school environments? For how many pupils is the home driving most the student’s
daily intake of nutrients to optimal. Such data are very important to
understand the true social impact of school lunches.

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"Ever seen a fat fox ~ Human obesity explored"

About Me

I graduated from University College Dublin in 1971 with an Masters in Agricultural Chemistry, took a PhD at Sydney University in 1976 and joined the University of Southampton Medical School as a lecturer in human nutrition in 1977. In 1984 I returned to Ireland to take up a post at the Department of Clinical Medicine Trinity College Dublin and was appointed as professor of human nutrition. In 2006 I left Trinity and moved to University College Dublin as Director of the UCD Institute of Food and Health. I am a former President of the Nutrition Society and I've served on several EU and UN committees on nutrition and Health. I have published over 350+ peer reviewed scientific papers in Public Health Nutrition and Molecular Nutrition and am principal investigator on several national and EU projects (www.ucd.ie/jingo; www.food4me.org). My popular books are "Something to chew on ~ challenging controversies in human nutrition" and "Ever seen a fat fox: human obesity explored"